docs: def _handle_template_end(self):
          """Handle the end of a template at the head of the string."""
          if self._context & contexts.TEMPLATE_NAME:
              if not self._context & (contexts.HAS_TEXT | contexts.HAS_TEMPLATE):
                  self._fail_route()
          elif self._context & contexts.TEMPLATE_PARAM_KEY:
              self._emit_all(self._pop())
          self._head += 1
          return self._pop()